Continuous chill casting of cladding on a continuous support



B- C. COAD Oct. 7. 1969 CONTINUCUS CHILL CASTING 0F GLADDING ON ACONTINUOUS SUPPORT Filed Nov. 8, 1965 3 Sheets-Sheet 1 M 1 o ,b!7//// MBA 4 544x27 Z Z w E A: .P

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Oct. 7. 1969 CONTINUOUS CHILL CASTING OF CLADDING ON A CONTINUOUSSUPPORT Filed Nov. 8. 1965 3 Sheets-Sheet z l km NUE

Oct 7. 1969 'e. c. COAD 3,470,939

CONTINUOUS CHILL CASTING 0F CLADD ING ON A CONTINUOUS SUPPORT Filed Nov.8. 1965 3 Sheets-Sheet 5 United States Patent T U.S. Cl. 164-275 6Claims ABSTRACT OF THE DISCLOSURE In one arrangement a hot melt ofmetallic cladding material is contained in a crucible to the bottom ofwhich is connected a cooling die which has a short inlet throat havingparallel sides, a lower outlet flare and cooling passages around thethroat and the flare. An electrical resistance heated metal core isdrawn through the melt and spacedly through the die throat. Gate meansin the melt controls its flow to the die. Initially some of the hot meltpartially freezes on the cooler substrate before it moves into the dieand additional melt partially freezes thereon which results in a verysmooth finish on the cladding without sticking in the die. Completion offreezing occurs in the flare of the die. In another form a length of thesubstrate is drawn up through a lower heated dish of the melt, thelatter being under pressure head from an elevated melt supply. In thiscase the die is inverted and located at the top above the melt for theupward passage of the core therethrough. In another form the core isguided along with some of the melt under a band and into the groove of acasting wheel wherein it freezes around the substrate and is then'drawnfrom the groove and the band stripped therefrom. In all forms aprotective atmosphere may be maintained around the core and the freezingcladding material, if required.

This invention relates to casting, and with regard to certain morespecific features, to continuous chill casting, that is, continuouscasting of liquid metal or nonmetal around a core of solid metal ornonmetal which acts as a heat-sink, abstracting heat from the liquidmetal, causing it to freeze; and which is fed continuously to the melt,to make continuous lengths of wire, rod, strip, tubing and the like, andreinforced or cored articles of that nature.

Among the several objects of the invention may be noted the provision ofrapid processes and means for obtaining more accurately dimensionedcontinuously cast products at higher rates of casting and smallerfinished size, such as wires, rods, strips and the like; the provisionof means for more reliably making such products; and the provision ofmeans for producing thicker cladding in cases in which inner cores orreinforcements are employed. Other objects and features will be in partapparent and in part pointed out hereinafter.

The invention accordingly comprises the apparatus, products and methodshereinafter described, the scope of the invention being indicated in thefollowing claims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

3,470,939 Patented Oct. 7, 1969 lCC FIG. 1 is a diagrammatic sectionillustrating one form of the invention;

FIG. 2 is a diagrammatic section showing a second form of the invention;

FIG. 3 is a side view illustrating a continuous casting machine forcarrying out another form of the invention.

FIG. 4 is an enlarged cross section taken on line 44 of FIG. 3;

FIG. 5 is a diagrammatic section illustrating a part a part of themachine shown in FIG. 3; and

FIG. 6 is a diagrammatic cross-sectional view showing another form ofthe invention.

Corersponding reference characters indicate corresponding partsthroughout the several views of the drawings. The drawings are not toscale, being diagrammatic.

Problems have been encountered in continuous casting in the undesirablesticking of cast material to the chilling dies employed. Another problemwas concerned with continuous casting of small cross sections. Suchcross sections when on the order of 1.0 square inch or less were subjectto easy breakage. The present invention overcomes these variousdifficulties.

Referring now more particularly to FIG. 1, there is shown at numeral 1 apart of a suitably heated container or refractory crucible for a melt 3.Heating means is diagrammatically indicated at 8. The melt may be of ametal or nonmetal which will solidify upon cooling. Such a melt, ifmetallic, may carry oxidation products such as slag or the like on thehot liquid surface. Such oxidation products are illustrated at 5.

Connected to the bottom 7 of the chamber 1 is an open cooling die 9. Thethroat 11 of this die includes a comparatively short upper inlet orforming portion 13 which has substantially parallel sides, thusproducing a cylindrical form of the correct cross section for the shapeof the product desired. Its lower or outlet portion 15 flares out asshown. Contained in the die around its cylindrical and flared portions13 and 15 are passages 17 for the circulation of a suitable coolant suchas water. Thus the die 9 is cooled throughout its length.

Projecting downwardly into the melt 5 is a guide nozzle 19 composed of asuitable heat-resistant or refractory material. Its outlet 21 ispositioned below the upper surface of the melt 3, which is to say, belowthe layer of oxidation products 5. The passage 23 through the nozzle 19is of a proper cross section to admit and freely guide core material 25for downward movement through the melt 3. Thus if the core material isround, as shown, the passage 23 in the nozzle 19 may be circular incross section. For core materials of other cross sections, the passagemay have other suitable cross sections for proper guiding action. Thecross section of the inlet portion 13 of the die 9 is larger and of ashape to provide for passage of the core material after application toit of an amount of whatever cladding material is desired. In thedrawings the section is circular for example, but other appropriatesections may be employed.

At numeral 27 is shown a stopper in the form of gate means, also made ofheat-resistant or refractory material. The stopper 27 surrounds andextends below the lower end of the nozzle 19. Its lower margin 29 isnear but spaced from the container bottom 7. Thus what may be referredto as a coating chamber 31 is provided around the core in its downwardmovement from the nozzle 19 to the die 9. The stopper 27 is verticallyadjustable. Any suitable means known in the art may be employed foradjustment, this being illustrated by the double dart 33. Thus the rateof flow of the melt 3 and of heat into the coating chamber 31 may becontrolled. The liquid level carried in this coating chamber 31 may beat (as shown) or below that in the remainder of container 1.

Suitable means for heating the core material 25 as it passes through theapparatus is provided, although not always necessary. Such means in thedrawing is illustrated as an electrical circuit 35 having slide contacts37 and 39, the former engaging the surface of the core 25 before itenters the nozzle 19 and the latter engaging the surface of the finishedcladding to be described. A voltage supply is shown at 36 and a currentcontrol at 38. As an alternative, the contact 39 may be made with thedie '9, in which case it need not be in brush form.

Operation of the form as shown in FIG. 1 is as follows, assuming forexample (but without limitation) that the core 25 is a continuous steelwire or rod and that the melt 3 is of copper:

The core is moved downward through the nozzle 19, coating chamber 31 andthe die 9, being at a comparatively cool temperature in its solid staterelative to the temperature of the hot melt 3. Thus the core will absorbheat from the melt as the core leaves the nozzle 19 and passes throughthe coating chamber 31. This heat flow is illustrated by the horizontaldarts 41. It has a partial freezing effect upon the melt around the corein the coating chamber 31. As a result, there will occur a more or lesssolidified coating or collar of the melt 3 within the coating chamber 31continuously forming as an attachment to the moving core 25 asillustrated at 43.

If the core 25 is small in section, the amount of heat that it canabsorb in passing is limited, so that the collar 43 in the coatingchamber 31 remains comparatively small in section. This is desirable forreasons to appear. In order to place a limitation upon the diameter ofthe collar 43 in cases in which the core is capable of absorbing largeamounts of heat (a large-section core, for example) or in which thespecific heat of the melt 3 is comparatively small, it may be desirableto heat the core by exciting the circuit 35, so that the amount of heatthat the core will absorb will be controllably limited. Thus the size ofthe collar 43 in the coating chamber 31 may be limited. Control of theelevation of the stopper 27 also has an effect in this regard, becauseit forms a resistance to heat and metal flow from the mass of liquidoutside of stopper 27 to the liquid in the coating chamber 31. Thehotter the core and the higher the stopper 27, the smaller will be theformation of the collar 43 and vice versa.

As the core 25 moves down, the clinging collar 43 continuously forms andmoves down with it into the comparatively large cylindrical annularspace within inlet portion or section 13 of the die 9. This spacereceives a peripheral inflow of hot liquid at 47 to add to the collar43. Since the die abstracts heat as shown by the darts 45, this tends tomore or less freeze the peripheral inflow to form additional material onthe collar 43. The exterior shape of this additional material isdetermined by the shape of the comparatively short parallel sides of theinlet section 13 of the die '9. The axial extent of the cylindricalinlet 13 of the die is short, so that in the comparatively short time ofpassage there will not occur a hard freeze in the die which might causesticking. In other words, the section 13 of the die forms the outside ofthe product by a smooth wiping or smearing action on a partially solidconsistency of the passing material, which may be called putty-like.Consequently, there is obtained a smooth accurate form without blemisheswhich passes down through the cooled flaring portion 15 of the die,where it is further cooled and solidification is completed. In itscompletely solidified state the resulting 4. cladding or matrix 54 iscapable of contact with the brush such as 39 for delivering heatingcurrent (if needed) to the core 25. In its completely solidified statethe product is capable of being drawn down by draw rolls such as shownat 49.

On the right-hand side of FIG. 1, the line bracket 51 indicates thechill-cladding zone in which the collar 43 is formed. The line bracket53 indicates What may be referred to as a continuous casting zone in theupper end of which accurate shaping is accomplished and in the lower endof which completion of solidification to the solid state isaccomplished.

It will be understood that although in FIG. 1 a plain cylindrical coreis illustrated, this may be of other forms such as woven or twistedcable, a solid strip, woven strip, multiple wires, rods or the like ofany desired cross sections. As to materials that may be used, the rangeis wide, such as, for example, steel tungsten, aluminum, molybdenum orthe like for the core material, and any appropriate metal such ascopper, zinc, lead, et cetera for the cladding material. Moreover, theinvention is applicable to the use of nonmetals. For example, the coremay be composed of carbon, being covered with materials such asaluminum, copper, the carbon to be burned out later to form a tubularproduct. Also, the core may be of metal and the cladding or matrix 54composed of one of the thermoplastic materials such as polystyrene,polyethylene, acrylics, fluoroearbons and the like.

The use of the straight and flared completely cooled form of the die 9shown in FIG. 1 is not limited to its location at the bottom of themelt. This is illustrated in FIG. 2, in which a clad wire 81 is shown asbeing made. In this case, numeral 57 indicates the heating chamber orpot for the liquid melt 59. This has a connection 61 to a dish or cavity63, the latter being at a lower elevation than the pot 57, so that ahead of liquid will maintain some pressure on the liquid in the dish 63.Heating coils 65 keep the melt in a liquid state in 57 and 63.

Attached to the upper side of the dish 63 is an open cooling die 67which is shown to an enlarged scale relative to other parts in FIG. 2.It is built like the die 9 in FIG. 1. However, it is inverted inposition. The die 67 again has a comparatively short straight-sidedthroat 69 and a flaring portion 71 extending therefrom. It is cooledthroughout its length by passages 73 which carry coolant. The die 67surrounds .an opening 75 in the top of the cavity 63. There is atendency under the pressure established by the liquid head H to pushmolten material through the opening 75 and through the die 67, asillustrated at 55. As shown on a reduced scale at 81, the wire or shapeas it is finished may be drawn up by draw rolls 78 and placed on a reel83. In this case the core material 2 is fed up through a sealing die 4and then up through die 67 where the cladding material 55 freezes to it.

Sometimes it is desired to make a continuous cored product in which thesurrounding matrix material is comparatively thick or bulky. In suchcases the rate of freezing of such matrix material must be madesufiiciently fast so that virtually no reaction occurs between it andthe core material. In order to introduce the reinforcing material intosuch thick matrix material, a conventional continuous casting method isused, as, for example, that shown in FIGS. 3 and 4.

In FIGS. 3-5 is shown another form of the invention in which FIG. 3illustrates a so-called Properzi casting machine. This employs a castingwheel 89 in which is a casting groove 91 which is illustrated as beingrectangular but which may have other cross sections. At 93 is a sheavefor a steel band 95 surrounding the groove 91 on the wheel 89. It isguided into an overlying position in groove 91 by a roller 96. At 101 isshown a container for a constantly maintained supply of melted material,for example metal, best shown in FIG. 5. The melt is numbered 103.Extending from the bottom of the container 101 is a spout 105 whichreaches into the groove 91 under the steel band 95.

I provide at numeral 97 a drum for a coil of reinforcing wire 99 to befed beneath the band 95 and ultimately into the groove 91. At numeral107 is a hollow refractory core guide for guiding core wire 99 throughthe melt 103 and into the spout 105. The lower end of the guide 107 islocated beneath the surfaceof the melt 103- in the container 101, asshown in FIG. 5.

Referring to FIGS. 3-5, operation is as follows:

The casting wheel 89 is driven to rotate by appropriate means (notshown). The melt flows out of the container 101 through the spout 105into the cool groove 91 under the belt 95. As it enters the groove itfreezes as at 115. The core wire 99 is fed down through the guide 107and the spout 105 and into position surrounded'by freezing material inthe groove. Thus the wire 99 is drawn into the freezing matrix at therate of matrix movement as the latter is carried around the wheel 89 andbecomes solid around the wire. The reinforced composite 116 thusobtained passes some distance around wheel 89 and then is strippedtherefrom by a stripper 109, being drawn off from belt 95 by a takeoffguide 113. The groove 91 cools as the composite 116 leaves it. This formof the invention provides a high-speed means for rapidly freezingcomparatively large amounts of matrix-forming metal, whereby virtuallyno reaction occurs between the reinforcing material 99 and the matrixmaterial surrounding it.

It is to be understood that the groove 91 may be of any form to give anyappropriate shape (without reentrant angles) desired for the matrixmaterial, and that several core wires 99 may be fed by obviousmodifications, or the core may be in the form of a solid ribbon, orwoven mesh or network of strip form. Various other shapes will suggestthemselves, both for the matrix material 115 and the containedreinforcement.

In FIG. 6 is shown a form of the invention wherein the collar-formingmeans of FIG. 1 is omitted. At 117 is shown a basin for a melt 119.Attached to the bottom of the basin 117 is a cooling die 125, havingcooling passages 121. At numeral 127 is shown a guide nozzle, the outletof which is below the surface of the melt 103. This is for guidingreinforcing material 129 through the opening 33 and die 125. This corematerial 129 may consist of wire, rod, strip, mesh or the like, as willbe clear from What has been stated above, the guide 127 beingappropriately shaped in cross section for the purpose. The core 129 isfed down as the melt runs through and freezes in passage through the die125 to form a solid matrix 131 around the core 129.

It is contemplated that in some cases the core material which is fedthrough the guide 127 shall be of the same composition as the melt 119and resulting matrix material 131. In such case the core material may bepreheated. It will form a support for the weight of the product as itlengthens and hangs from the die, thus avoiding tearing of anysemifrozen material in the forming throat 133 of the die 125 andpermitting higher casting speeds than possible without reinforcement orsupport. A heating circuit is illustrated at 130.

Another example of a strip such as 129 that may be used as core materialis one composed of surface-anodized aluminum. Surface anodization ofaluminum consists of an oxide skin and acts as a barrier between thealuminum strip and the matrix-forming melt 119, such as, for example,copper. Thus even though the anodized aluminum may be melted as itenters throat 133, there will be no alloying with the copper melt beforeboth of them solidify. It will be understood that this principle mayalso be applied to the FIG. 1 form of the invention in which the coremay be made of anodized aluminum and the melt 3 composed of copper.

It will be understood that in all forms of the invention,

if a protective inert or other atmosphere or vacuum is required forworking any particular materials or metals, such can be obtained inknown manner by placing the apparatus or appropriate parts thereof in achamber, containing such an atmosphere or in which a vacuum is formed.Or in the case of a gaseous atmosphere appropriate jets of the same maybe employed, as illustrated for example at numerals 135 and 137 in FIG.6.

It will be understood from the above that the invention contemplatesthat the matrix-forming melt and the core or reinforcing material. whenused may be selected from a wide category of both metals and nonmetals.Both may be the same material. Or either may be metal and the other anonmetal. For example, in the form of the invention shown in FIG. 1, thecore 25 may be a good electrical conductor, while the matrix-formingmaterial may be a poor conductor or an insulator.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above apparatus, products andmethods without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe ac companying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. Continuous chill-casting apparatus comprising a vessel having anoutlet and containing a heated melt of cladding material under pressureat said outlet, a fixed die connected at said outlet shaped for spacedlyreceiving therethrough a continuous solid substrate material, said diehaving substantially parallel axially disposed sides in a comparativelyshort inlet throat portion and having a comparatively longer flaringoutlet portion extending from the throat portion, said throat portionreceiving cladding material from the vessel and around the substratematerial, said die having heat-exchange coolant circulating passagesdisposed both around said short inlet throat and the flaring oultet,means for continuously moving the substrate through the melt and the diein that order, said substrate being in a comparatively cool conditionwith respace to that of the melt of cladding material as it approachesthe die thereby to abstract heat from the melt and tending to freeze itas it approaches said inlet throat, said cooled throat of the diesemifreezing the melt to form a putty-like collar in moving the contactwith the throat wall thereby to shape the putty-like collar byexteriorly smearing it in its putty-like condition as it moves throughand emerges from the throat into said flaring outlet portion of the die,the cooled flaring portion freezing to a solid condition thesmear-finished cladding material emerging from the throat and withoutcontact therewith, thereby to preserve intact its solid finish.

. 2. Apparatus according to claim 1 wherein the die is located below themelt for receiving material therefrom, said pressure being establishedby the hydrostatic pressure of the melt.

3. Apparatus according to claim 1 wherein the die is located above aportion of the melt, and means for generating said pressure to force themolten material up through the die throat.

4. Apparatus according to claim 1 including a verticaly adjustable gatemeans in the pool for controlling flow of the melt therefrom into thedie.

5. Apparatus according to claim 1 including electrical resistanceheating means for the core as it passes through the melt and the die forcontrolling the thickness of said initially paratially frozen material.

6. Apparatus according to claim 3 wherein said lastnamed means comprisesa volume of the molten material connected with said portion of the meltto provide hydrostatic pressure therein to force the melt up through thedie.

(References on following page) References Cited UNITED STATES PATENTSNorman 164-275 XR Schultz 164-64 XR Pike 164-275 XR Hudson 164-275Schultz 164--275 Reynolds 164-275 XR Priaroggia et al. 164-86 X Hancock164-86 Monnot 164-282 X Eliot.

Chadwick et al. 164-283 X Hartland.

FOREIGN PATENTS Suomi.

J. SPENCER OVERHOLSER, Primary Examiner 10 V. RISING, Assistant ExaminerUS. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 '0,939 Dated October 7 1 969 Inventor(s) Brian C Coad It is certified thaterror appears in the aboveand that said Letters Patent are herebycorrected as "1 Column (i line O, for "oultet" read "outlet"; lines 19-13, for "r'espace" read "respect"; line 17, for "moving; the contact"read "moving contact"; lines 634M, for "verticaly" read "vertically";line 69, for "paratially" read "partially".

identified patent shown below:

GIG-"JED AND SEALED FEB 171970 Amt:

Flewher. Ir. wmxm 1:. 50mm, .1 Anesfing Officer commissioner nts

